from collections import defaultdict

n=int(input())
A=list(map(int,input().split()))

ok_left,ok_right=0,0
left,right=defaultdict(int),defaultdict(int)
for a in A:
    right[a]+=1
    if right[a]==2:
        ok_right+=1
        
ans=[]
for j in range(n-1):
    left[A[j]]+=1
    if left[A[j]]==2:
        ok_left+=1
    
    right[A[j]]-=1
    if right[A[j]]==1:
        ok_right-=1
    
    if ok_left==0 and ok_right==0:
        ans.append(j+1)

print(len(ans))
print(*ans)